Actuator

ABSTRACT

An actuating device formed of elastic tubing having circumferential reinforcement therein and having a portion of the transverse periphery with longitudinal cords of tension resistant material along only one side of the tubing. In the relaxed state the device is substantially linear, but upon introduction of a pressurized fluid therein the tube curls about the side having the longitudinal reinforcing cords and upon release of the pressurized fluid the device returns to substantially a linear state.

O United States Patent 11 1 1111 3,

England Dec. 9, 1975 ACTUATOR 3,481,254 '12/1969 Wetherbee 92/92Inventor: Jo S. g and c y hoga Fans 3,561,330 2/1971 Rich 92/92 OhioFOREIGN PATENTS OR APPLICATIONS 73 Assignee; The Goodrich Cmnpany,6,704,918 4/1967 Netherlands 3/l.2

Akron, Ohio Primary Examiner-Edgar W. Geoghegan [22] Flled' 1968Assistant ExaminerAbraham I-Iershkovitz [21] Appl. No.: 754,225Attorney, Agent, or Firm-W. A. Shira, Jr.

52 US. (:1. 92/92; 73/410; 73/418; ABSTRACT 138/119; 138/132 Anactuating device formed of elastic tubing having Cl. circumferentialreinforcement therein and having a [58] Field of Search 92/90, 91, 92,94, 1.2; portion f the transverse periphery with longitudinal 138/118,177; 73/418, 410 cords of tension resistant material along only one sideof the tubing. In the relaxed state the device is sub- References Cltedstantially linear, but upon introduction of a pressur- UNITED STATESPATENTS ized fluid therein the tube curls about the side having1,161,376 11/1915 Bristol 73/410 the longitudinal reinforcing cords andupon release of 2,642,091 6/1953 Morin 92/90 the p sur fluid the devicereturns to substantially 3,253,854 5/1966 Hollander... 92/92 a linearstate. 3,334,643 8/1967 Shamos 137/98 3,343,864 9/1967 Baer 294/99 11Clalms, 2 Drawmg Figures US. Patent Dec. 9 1975 INVENTOR m gonuS.ENGLAMD ATTY.

ACTUATOR BACKGROUND OF THE INVENTION Hydro-mechanical actuators arecommonly used for providing movement through limited distances. Examplesof such devices are to be found in equipment for handling materials atelevated temperatures, at cryogenie temperatures and where high levelsof radioactivl ity preclude human operators from close proximity to thematerial being handled. Such actuators are also used to provide forceassistance for moving linkage members and other components of machinesand ma nipulative devices.

One area of possible use for such devices is that of providing a meansof assisting persons who, through physical affliction, have lostpartially or completely the use of some of their bodily limbs. Variousmechanical expedients have been devised to provide aid in operativelymoving incapacitated bodily limbs, but these expedients have beenunwieldy and difficult to maintain in proper working order due to theirmechanical complexity. Heretofore, such devices have utilized arms andpinned linkages capable of providing limb assist by translatory motionand rotational movement about pivot pins. In order to get accurate andrepeatable multi-directional motion from such mechanisms, the componentsmust be intricately designed and must be made with a high degree ofprecision and are, therefore, quite costly.

Furthermore, the bulkiness and weight of mechanical actuators for aidingthe motion of human limbs is often a source of annoyance andembarrassment to the patient wearing the devices, in view of theunsightly appearance of the complex of linkages and pinned connections.In order to avoid the embarrassment of wearing such orthostatic orprosthetic devices, many persons suffering from partial or total loss ofuse of some limbs prefer instead to remain without the full use of theirlimbs.

SUMMARY OF THE INVENTION This invention relates to a fluid pressureoperated actuating device for providing movement through limiteddistances. The invention is in the form of an elongated flexible tubehaving a longitudinally extending opening closed at one end, the tubebeing easily and freely flexed in its natural or linear state, butassuming an arcuate configuration about an axis substantially at rightangles to its length upon introduction of a pressurized fluid into theopening. This action is the result of the tube having a portion of itstransverse periphery of lesser longitudinally extensibility than theremainder of the periphery. In the preferred embodiment this is madepossible by forming the tube of elastomeric material with substantiallyinextensible longitudinally extending reinforcing cords disposed thereinin a region which does not exceed one-half of the transverse peripheryof the tube. The tube preferably also has substantially inextensiblereinforcing cords radially inward of the longitudinal cords andextending at right angles to the length of the tube. The layer oflongitudinal reinforcing cords along one side restrains the device, suchthat upon internal pressurization, the device changes from a linearconfiguration to a curved state with the side having the tension cordstherein forming the radially inner surface of curvature.

2 The device has a variety of uses one of which is attachment todisabled or handicapped human limbs for inducing motion thereof byselectively internally pressurizing the device to produce the desiredamount of curvilinear motion and hence movement of the attached limb.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the actuatorwith the end portions broken away to show the terminal fittings; thedevice being illustrated in full lines in its curled pressurized state,and the unpressurized configuration being indicated in dashed lines; and

FIG. 2 is an enlarged transverse section taken along thesection-indicating lines 2-2 of FIG. 1.

DETAILED DESCRIPTION Referring now to FIG. 1, the presently preferredembodiment of the actuator 10 is shown in actuated condition wherein thetube 11 is pressurized internally by a fluid. The tube 11 is in the formof an elongated elastically flexible tube having one end closed. Thetubing has an opening extending longitudinally therethrough, whichopening is closed at one end. A longitudinal portion, not exceedingone-half the transverse periphery of the sidewall thereof, is made of amaterial which has the property of being longitudinally inextensible.The remainder of the tubing 11 is made of exten sible material. Uponintroduction of a pressurized inflating fluid through the opening in thetube, the tube is caused to curl about an axis perpendicular to itslongitudinal direction.

In the preferred form of the invention, the tube 11 is made ofelastomeric material, with the inextensible portion comprisinglongitudinally extending reinforcing cords 15 embedded in the sidewallof the tube. One end of the actuator is closed, preferably, by a plugmeans 13 securely fastened in the bore of the tubing 11. In thepreferred form of the invention, the actuator 10 is fabricated andvulcanized in the substantially linear state shown by the dashed linesin FIG. 1.

Referring now to FIG. 2, the carcass of the tubing 11 is shown in across-sectional view. The tubing has a polygonal shape in the preferredform with preferably two opposite parallel sides 11a and 11b. Thereinforcing cords 14 comprise at least one layer embedded closelyadjacent the inner periphery of the tubing. The cords 14 are disposedsubstantially perpendicular to the length of the tubing and arepreferably in equally spaced parallel relationship with each cordextending continuously around the wall of the tubing with the ends ofthe cords overlapping each other to form a splice. In the presentlypreferred form of the invention, the cords 14 are made of strandedtextile fibers, but the cords may also be made of monofilamentarymaterial, or from stranded metal filaments where high pressures arerequired for actuation.

Embedded radially outwardly of the circumferential cords 14 is asubstantially planar layer of longitudinally extending parallel cords15, with each cord running continuously the length of the actuator. Thecords 15 are preferably disposed radially outward of the cords 14 in alayer which extends transversely the width of one of the parallel sides11a of the polygonally shaped tube 11. The cords 15 provide resistanceto elongation for the side Ila when the tube 11 is pressurizedinternally. The opposite side 11b of the tube is permitted to elongatewhen the tube 11 is pressurized internally and the tube carcass 11 tendsto curl or coil about the side 11a. Thus, the actuator may, byintroduction of a fluid at sufficient pressure therein, be caused toassume the configuration shown in FIG. 1.

A port means 12 is provided for introducing pressurizing fluid therein.In the preferred form of the invention illustrated in FIGS. 1 and 2, theport means 12 is a small rigid tube 12, having a bore diameter smallerthan the opening in the tube 11, which rigid tube 12 is securelyfastened and sealed therearound in one end of the tube 11 in a mannereffecting a fluid pressure-tight seal such that fluid passage is allowedonly through the port means 12. Upon releasing the pressurized fluidfrom the interior of the tubing 11, the actuator uncurls due to theelastic nature of the tubing material to assume again a substantiallylinear configuration as shown by the dashed lines in FIG. 1. Theactuator is thus substantially linear in the tie-actuated orunpressurized state, curls upon pressurization, and returns to theuncurled linear state again upon de-actuation without the aid of anyexternal force assistance.

Although this novel actuator will readily lend itself to many and varieduses, the particular application of the presently preferred embodimentis a prosthetic device. When the actuator is attached, for example,along a bodily limb with the inextensible side 11a contacting thesurface of the limb and extending along the outside of one or morejoints, for example the knuckles of a finger, the limb may be moved bypressurizing the actuator and causing it to curl. As the internalpressure is subsequently released from the tubing, the actuator nolonger tends to curl about the tension resistant side 1 la, but returnsto its original linear configuration, thus tending to straighten thelimb.

The present invention thus comprises an actuator formed of flexiblematerial preferably elastomeric tubing having a polygonal cross-sectionwith tension reinforcement cords embedded longitudinally along only oneside which cause the actuator to curl about an axis perpendicular to thelength of the actuator when pressurized internally. However, it is not arequirement of the invention that the tubing 11 have a polygonalcrosssection or that there be two opposite parallel sides and the tubingmay have a generally closed curvilinear shape, or any polygonal shape,as for example triangular. Furthermore, the tubing of the actuator neednot be made of elastomeric material. Any suitable fluid imperviousmaterial may be used which is capable of elastically returning to thelinear configuration in the unpressurized state without the aid ofexternal force assistance.

Persons having ordinary skill in the art may see further adaptations andmodifications to the invention which is limited only by the spirit andscope of the appended claims.

I claim:

1. An actuating device comprising: an elongated elastic tube having anopening extending longitudinally therein with one end closed and adaptedto have fluid under pressure introduced therein, the said tube beingformed of elastomeric material with at least one tension layer having aplurality of longitudinally extending substantially inextensibleweftless reinforcing cords embedded therein and with the said layerextending transversely of the tube less than one-half of the transverseperiphery thereof to provide a region having lesser longitudinalextensibility than the remainder of the periphery so that the tube iscaused to assume an arcuate configuration about an axis at substantiallyright angles to its length upon introduction of a pressurized fluid intosaid opening.

2. The device defined in claim 1, further comprising at least one ply ofsubstantially inextensible reinforcing cords disposed circumferentiallyand radially inward of said tension ply with each cord extending aroundthe tube at substantially right angles to the tube.

3. The actuating device defined in claim 1, wherein the said tube has apolygonal transverse section with two opposite parallel sides with thesaid tension cords disposed in only one of the said parallel sides.

4. The device defined in claim 1, wherein the cords in said tension plyare made of stranded metal filaments and the said circumferential cordsare made of textile material.

5. The device defined in claim 1, wherein the cords in the said tensionply and the circumferential cords are made of stranded metal filaments.

6. The device as defined in claim 1, wherein a. the said opening is acontinuous bore through the length of said tube,

b. the said closed end is provided by plug means inserted in one end ofsaid bore, and

c. a fluid port means is provided in the other end of said bore, whichport means is adapted to be con nected to a source of fluid underpressure.

7. An elongated tubular body comprising a structure which is limitedagainst circumferential extension substantially uniformly throughout itslength, a longitudinal section of said structure being limited againstextension in the longitudinal direction, the remainder of said structurebeing reversibly extensible in said longitudinal direction, wherebyinflation of said structure with a fluid will cause said structure toflex.

8. An elongated tubular body comprising a flexible structure, means forlimiting said structure against circumferential extension substantiallyuniformly throughout its length, means for limiting a longitudinalsection of said structure against extension in the longitudinaldirection, the remainder of said structure being reversibly extensiblein the longitudinal direction, whereby inflation of said structure witha fluid will cause said structure to flex.

9. A tubular body according to claim 8 in which said means for limitingagainst circumferential extension comprises elongated substantiallynon-extensible material oriented transversely to said longitudinaldirection in restraining relation with the walls of said body.

10. A tubular body according to claim 8 in which said means for limitingsaid longitudinal section against extension comprises flexible butsubstantially nonextensible material oriented in said longitudinaldirection in restraining relation with said longitudinal section.

11. A tubular body according to claim 8, in which said structure is atube of flexible elastic material, and said limiting means are cord-likemembers of substantially non-extensible material.

1. An actuating device comprising: an elongated elastic tube having anopening extending longitudinally therein with one end closed and adaptedto have fluid under pressure introduced therein, the said tube beingformed of elastomeric material with at least one tension layer having aplurality of longitudinally extending substantially inextensibleweftless reinforcing cords embedded therein and with the said layerextending transversely of the tube less than one-half of the transverseperiphery thereof to provide a region having lesser longitudinalextensibility than the remainder of the periphery so that the tube iscaused to assume an arcuate configuration about an axis at substantiallyright angles to its length upon introduction of a pressurized fluid intosaid opening.
 2. The device defined in claim 1, further comprising atleast one ply of substantially inextensible reinforcing cords disposedcircumferentially and radially inward of said tension ply with each cordextending around the tube at substantially right angles to the tube. 3.The actuating device defined in claim 1, wherein the said tube has apolygonal transverse section with two opposite parallel sides with thesaid tension cords disposed in only one of the said paRallel sides. 4.The device defined in claim 1, wherein the cords in said tension ply aremade of stranded metal filaments and the said circumferential cords aremade of textile material.
 5. The device defined in claim 1, wherein thecords in the said tension ply and the circumferential cords are made ofstranded metal filaments.
 6. The device as defined in claim 1, whereina. the said opening is a continuous bore through the length of saidtube, b. the said closed end is provided by plug means inserted in oneend of said bore, and c. a fluid port means is provided in the other endof said bore, which port means is adapted to be connected to a source offluid under pressure.
 7. An elongated tubular body comprising astructure which is limited against circumferential extensionsubstantially uniformly throughout its length, a longitudinal section ofsaid structure being limited against extension in the longitudinaldirection, the remainder of said structure being reversibly extensiblein said longitudinal direction, whereby inflation of said structure witha fluid will cause said structure to flex.
 8. An elongated tubular bodycomprising a flexible structure, means for limiting said structureagainst circumferential extension substantially uniformly throughout itslength, means for limiting a longitudinal section of said structureagainst extension in the longitudinal direction, the remainder of saidstructure being reversibly extensible in the longitudinal direction,whereby inflation of said structure with a fluid will cause saidstructure to flex.
 9. A tubular body according to claim 8 in which saidmeans for limiting against circumferential extension comprises elongatedsubstantially non-extensible material oriented transversely to saidlongitudinal direction in restraining relation with the walls of saidbody.
 10. A tubular body according to claim 8 in which said means forlimiting said longitudinal section against extension comprises flexiblebut substantially non-extensible material oriented in said longitudinaldirection in restraining relation with said longitudinal section.
 11. Atubular body according to claim 8, in which said structure is a tube offlexible elastic material, and said limiting means are cord-like membersof substantially non-extensible material.